Yes, check your new solder joints. From what I can see some don't look real "clean". Did you use a very small (micro) solder tip and very thin electronic solder? Also, I think I see evidence of solder bridging. Did you spill some hot solder where it should not be? Reheat those new joints until the joint goes from dull to very shiny. Actually, I would do every one that holds the leads to the lamps that are no longer working. Having once worked as an electronic tech I would also scan the board very carefully around all lamps and ground points. Use a high-power magnifying glass and strong light. Doing this you can sometimes see hairline cracks in new and old joints; a dead giveaway to a poor solder job. I've embarrassed myself many times.

Funny that I was working on the same thing yesterday, & today I see this post.
Mine was the center display bulb, & what I did was to buy a 12V one from Radio Shack.
Then when I put it all back together the lower corner button was off. I opened the radio again & it was blown. I think they are to delicate so this time Im doing the job on top of a towel.

My radio has the same problems. Funny thing is though, is that when I press hard on the faceplate of the radio (with it installed) my lights will come on and stay on for a while. Eventually they'll go back out, but pressing hard on the faceplate turns them on again. I'm guessing that the copper colored forks (2 of them apprx 3/8" wide) that contact between the faceplate and the unit itself are possibly a ground????